Abstract: Graphene Nanostructures as a New Platform for Ultrasensitive Multiplexed Biological Sensors Abstract The detection and quantification of chemical and biological species are central to fundamental biological research and medical diagnostics. The current detection methods often require complicated sample preparation/amplification procedure, and take significant time to detect, identify and characterize biological targets. The concept of ChemFET, in which the conductance of a transistor is modulated by the electric field generated by the presence of chemical or biological molecules, offers the potential for label- free direct electrical detection, but is limited by low sensitivity. Here I propose to exploit a newly discovered material (graphene, graphene nanoribbon or graphene nanomesh) as ChemFET to directly transduce specific molecular binding events into electrical signals for highly sensitive, selective and label-free detection of biological species. Systematic studies will be conducted to create graphene nanostructures and nanodevices with tunable band gap and electronic properties, to develop generic linkage chemistry for bioconjugation of specific receptors and passivation of undesired active sites, and to integrate large arrays of nanosensors for multiplexed detection of multiple analytes. The use of high mobility, atomically thin graphene nanostructures ensures exceptional sensitivity not available with conventional materials, and therefore enables a new generation of ultrasenstive nanosensors. The extreme sensitivity and rapid temporal response may also enable entirely new sensing schemes such as stochastic sensors. The development of ultrasensitive multiplexed nanosensors can open many exciting opportunities for highly parallel detection of proteins, nucleic acid, virus, and other biological species from various body fluids without sophisticated purification/amplification process, and enable fast, high fidelity, low cost diagnosis. The high throughput monitor of a large number of distinct sensors can generate a huge amount of data to decipher the complex signal differences and identify fine molecular prints that distinguish patients with certain diseases from the healthy people, and therefore contribute to the development of disease-fingerprinting systems and personalized medicine. Public Health Relevance: The detection and quantification of chemical and biological species are critical for fundamental biological research and medical diagnostics. The central goal of this project is to develop a general platform technology using atomically thin graphene nanostructures (e.g. graphene and grapheme nanoribbon or graphene nanomesh) to directly transduce specific molecular binding events into electrical signals, and create multiplexed biological nanosensors for highly parallel, sensitive and selective detection of proteins, nucleic acid, virus, and other biological species. The proposed sensing approach has the potential to enable a new generation of point-of-care diagnostic tools with multiple advantages over conventional detection schemes, including unprecedented sensitivity, label-free detection, real time electrical data readout, and low cost detection instrumentation.